In recent years, information exchange through the Internet has experienced exponential growth. Therefore, a variety of search engines have been developed for quickly and accurately searching information through the Internet has been developed.
However, since all of the prior search engines are designed such that they can search only the information which exactly complies with the word the user inputs, when the user does not know the word complying with the information he wants to find, it is difficult to find the information.
Accordingly, there is a need for a search engine capable of finding the information desired by the user precisely and quickly.